Sorry, by flattened I meant that it looks fat. The point is, if I want to see the video in the computer at 4:3 (768×576) it looks fat. Instead to see it properly I have to see it at 720×576, which is not 4:3!
When capturing and watching what’s captured in any media player, it shows it 4:3 and flat. Later if I compress it with flash compressor, I can only do it at a ressolution equivalent to 720×576. The result is the image looks proportionally good, but not 4:3. The same with After Effects, when I say that I want to show it with square pixel, the image is no longer 4:3.